Jan. 3, 2011 -- Young people who say they've abstained from sexual intercourse may not be telling the whole truth, an important finding in the ongoing battle against the spread of sexually transmitted diseases.

Researchers at Emory University in Atlanta examined data on 14,012 young adults in their early 20s, who completed a computer-assisted interviewing survey and provided a urine specimen aimed at detecting three common STDs: chlamydia, gonorrhea, and trichomoniasis.

More than 10% of the young people found to have at least one of the STDs had reported not having penile/vaginal sexual intercourse in the past 12 months. This suggests that routine screening of STDs may be a better way to reduce transmission of diseases.

Young People May Not Tell Whole Truth About Sex Lives

The study is reported in the Jan. 3, 2011, issue of Pediatrics. Self-reported sex in the previous year was significantly linked to testing positive for one of the STDs. However, more than 10% of the people who tested positive reported being abstinent in the previous year.

About 6% of youths who tested positive for at least one of the STDs reported no lifetime history of penile/vaginal sex.

Self-Reported Sexual Activity Not Reliable

Study findings indicate that "sole reliance on young adults' self-reported penile/vaginal sexual activity as a marker for STD acquisition risk may be imprecise and further, could be problematic," the researchers write.

They argue that future research should attempt to find ways to reduce "discrepant" reports by young people about their sexual activity.

The researchers note that they did not collect information about anal sex among men and that some cases of chlamydia may persist 12 months after sexual intercourse. And study participants only indicated whether they'd had sex had in the past 12 months.

"Given the length of the reporting interval, the previous 12 months, young adults' retrospective recall could be inaccurate," the researchers write. However, they add that "volitional underreporting" could explain discrepancies between self-reports and facts.

The findings suggest that doctors should do more than just ask young people about their sexual activity.

"Importantly, our findings reveal that if pediatricians and adolescent medicine physicians do not test all young people, there are likely a substantial number of missed cases of STDs that will go undiagnosed, untreated, and spread to future sex partners," the researchers write.